Changes between Version 3 and Version 4 of Documentation/UserGuide/DifferencesNetcdf

Timestamp:

2014-12-11T19:34:04+01:00 (9 years ago)

Author:

luyssaert

Comment:

--

Documentation/UserGuide/DifferencesNetcdf

@@ -1 +1 @@
 = How to check whether two netcdf files are identical =
+
+=== cdo diffv ===
 
 Rather than comparing plots, its faster and more precise to compare whether two netcdf files (i.e. a history or restart file between 2 model versions) are numerically identical. The follow command works on asterix and obelix
@@ -6 +8 @@
 cdo diffv   path_file_1   path_file_2 > output_file_name.txt
 }}}
+ADVANTAGE: the output file tells you which fields are different. Be aware, though that this method works best for smaller netCDF files. If your history file is more than a few megabytes, the output text file may be many hundreds of megabytes. In that case, the md5sum command may be a better option. 
 
-Be aware, though that this method works best for smaller netCDF files. If your history file is more than a few megabytes, the output text file may be many hundreds of megabytes. In that case, using an analysis package such as IDL to calculate the differences between variables is better.
+=== md5sum ===
+
+If you expect that the files are identical (bit by bit) you can use
+{{{
+md5sum path_file
+}}}
+as a result you will get a code. Run the same command on the second file and only when the code is identical for both files, the files are exactly the same.
+
+DISADVANTAGE: you only know whether the files are identical or not. If not, you have no idea which fields are different.